I think the Sabres are making a mistake signing Mittelstadt this early. Yes his number look great and he had a killer WJC, but he's still very physically immature.
I think they should be patient - he's not the difference between making the playoffs and not. They should be letting him develop another year. Focus on rebuilding the defense and letting him continue to mature. The last thing they want is to have this super talented kid come in and get dragged into the shitshow.
It's not like the Sabres are in a hurry, they have a lot of holes to fill. What's the rush? Let him develop in a positive atmosphere.
My brother is a hardcore Sabres fan (I live around Buffalo) and he's absolutely terrified that Mittelstadt is going to get ruined.